Electrosurgical instruments are well known in the surgical arts. These instruments utilize radio frequency energy provided by a generator to power electrosurgical instruments having various configurations, e.g., pencils, probes, electrosurgical scissors, electrosurgical forceps, etc. The instruments, when in contact with tissue, allow for the passage of a high frequency current along a pathway from an active electrode, through tissue, and then to a ground or return electrode. The current flow allows the surgeon to cut or coagulate tissue by varying parameters such as power, contact time, wave form, frequency, etc.
There are two types of electrosurgical systems that are commonly used: monopolar systems and bipolar systems. The monopolar systems use an instrument with a single active electrode. A grounding pad having a substantially large surface area is mounted to the patient's body to provide a return path back to the generator. In a monopolar system, current will flow from the active electrode on the instrument, to the tissue site, and then through the patient's body to the grounding pad. In contrast, bipolar systems typically utilize an instrument having both an active electrode and a return electrode mounted to the instrument. A patient grounding pad with its attendant disadvantages is not required. The current path in a bipolar system is from the active electrode, through the tissue site, and then back to the return electrode. The current path is much more localized in a bipolar system when compared to a monopolar system.
An electrosurgical system will typically consist of an electrosurgical generator, an electrosurgical probe or instrument, and a connecting cable. Conventional electrosurgical cables must provide conductors having sufficient size to safely conduct the electrosurgical power produced by the generator. The cables must be flexible and compact and must have sufficient electrical insulation. The cables must have connectors on both ends for electrically connecting the generator to the instrument. Since there is a fundamental difference in the operation of bipolar and monopolar electrosurgical instruments, it is an important safety consideration to prevent bipolar instruments from being inadvertently connected to monopolar electrosurgical generators. In addition, bipolar instruments typically have two electrical connectors while monopolar instruments only require one connector, i.e., the grounding pad is connected separately to the generator. Bipolar instruments must be designed so that the additional electrical connector and cable does not impede the surgeon when using the bipolar instrument in a surgical procedure.
Cables know in this art may be made from conventional co-axial cable or conventional "zip" cable. The cables typically have banana plug connectors mounted on one or both ends. One end of a cable is connected to an electrosurgical generator, while the other end of the cable is connected to an electrosurgical instrument. The cables may also have specially configured plugs on the generator end so that the cable can be used with only specific types of generators, for example, for use only with bipolar generators.
Although conventional bipolar cables perform adequately, there are several problems attendant with their use, including adjustability of cable length and secure mounting to terminal posts. In addition, when using a bipolar instrument such as bipolar scissors which have electrodes that are moveable with respect to each other, conventional bipolar cables may be deficient since they do not allow for such movement.
Accordingly, there is a need in this art for improved bipolar cables, and for bipolar cables that can be used with bipolar instruments having moveable electrodes such as bipolar electrosurgical scissors.